Unique Enhancement of the Whispering Gallery Mode in Hexagonal Microdisk Resonator Array with Embedded Ge Quantum Dots on Si.

The coupling between the quantum dots (QDs) and silicon-based microdisk resonator facilitates enhancing the light-matter interaction for the novel silicon-based light source. However, the typical circular microdisks embedded with Ge QDs still have several issues, such as wide spectral bandwidth, difficult mode selection, and low waveguide coupling efficiency. Here, by a promising structural modification based on the mature nanosphere lithography (NSL), we fabricate a large area hexagonal microdisk array embedded with Ge QDs in order to enhance the near-infrared light emissions by a desired whispering gallery modes (WGMs).

Wavelength Modulation Characteristics of Metal Gratings on Si-Based Blocked-Impurity-Band (BIB) Terahertz Detectors.

In this work, the wavelength selection characteristics of metal gratings on Si-based blocked-impurity-band (BIB) detectors in the terahertz band were studied by performing experiments and a finite difference time domain (FDTD) simulation. The transmission spectra of metal gratings with different periods on 130 μm intrinsic Si substrates were measured. When the metal grating period increased from 16 to 20 to 32 μm, the peak position of the spectrum moved from 21.

Optimization of Pixel Size and Electrode Structure for Ge:Ga Terahertz Photoconductive Detectors.

To investigate the effects of the pixel sizes and the electrode structures on the performance of Ge-based terahertz (THz) photoconductive detectors, vertical structure Ge:Ga detectors with different structure parameters were fabricated. The characteristics of the detectors were investigated at 4.2 K, including the spectral response, blackbody response (), dark current density-voltage characters, and noise equivalent power (NEP).

Nanoscale growth of a Sn-guided SiGeSn alloy on Si (111) substrates by molecular beam epitaxy.

Here, SiGeSn nanostructures were grown molecular beam epitaxy on a Si (111) substrate with the assistance of Sn droplets. Owing to the thermal effect and the compressive strain induced by a lattice mismatch, Si and Sn atoms were successfully incorporated into the Ge matrix during the Sn-guided Ge deposition process. A low growth temperature of 350 °C produced a variety of SiGeSn nanostructures of different sizes, attributed to the variation of the initial Sn droplet size.

The photoelectric response of the graphene/GeSi QDs hybrid structure.

In this work, the photoelectric response properties of the graphene/GeSi QDs hybrid structure were demonstrated by measuring the I-V curve, and the incident photon-to-current conversion efficiency (IPCE). The maximal on-off ratio of the current value reaches 1500 at 10 K, due to the competition between the carrier freeze-out effect and the recombination center effect. The IPCE of the hybrid structure under different incident light indicated that the photoelectric response of hybrid structure is most sensitive to the ultraviolet light (325 nm), which is attributed to the enhanced ultraviolet absorption of graphene surface plasmon in the hybrid structure.